endocrine system Flashcards
exocrine gland
secrete products directly into ducts
endocrine glands
secrete products (hormones) into blood and target effector organs
major exocrine glands
found in digestive system, sweat glands, salivary glands, milk ducts, subaceous glands, tears (lacrimal glands)
major endocrine glands
hypothalamus, anterior pituitary, posterior pituitary, thyroid, parathyroid, adrenal cortex and medulla, pancreas, gonads
major organ with endocrine and exocrine function
pancreas
exocrine portion of pancreas
digestive enzymes
endocrine portion of pancreas
insulin and glucagon
what are the exocrine and endocrine functions of the liver
exocrine: secretes bile
endocrine: secretes angiotensin
paracrine signaling
signaling acts on nerby cells
- heavily involved in embryonic differentiation
which type of signaling is thought to be associated with cancer
autocrine
juxtacrine singaling
cells must be in close contact for communication
merocrine cell
if cell releases secretions through exocytosis
merocrine cell
secretion via exoctyosis
merocrine cell
if cell releases secretions through exocytosis ec
eccrine glands
merocrine sweat glands
apocrine glands
release through membrane bound vesicles
- mammory and sweat
holocrine secretions
rupture of plasma membrane and releasing product
- subaceous glands
peptide hormones
amino acid based hormones that are polar and must have a membrane receptor
steriod hormones
nonpolar and derived from cholesterol
4 ring structure
can diffuse readily across plasma membarne and bind to dna
primary signal in peptide homrones
peptide hormone
why do hormones require transport proteins in the blood
because they are not soluble
nonspecific steroid transport protein
albumin
once in the cell what do steriod hormones bind to
nuclear receptors
major effect of steroid hormones in the cell
gene expression
preprohormones
early precursors of PEPTIDE hormones that are transferred to the rough ER to become prohormones
prohormones
inactive immediate precusors to peptide hormones
where are prohormones cleaved to become complete peptide hormones
golgi
steroid hormones are derived from what
cholesterol in smooth ER
are there intermediate stages of steriod hormone formation
no
only peptide hormones go through pre and pro stages
are peptide hormones soluble in blood
yes, this is why they do not need a transport protein like steroids
which type of hormone has more rapid effect? which one is the most long term
peptide and steroid respectively
typical functions of steroid hormomes
sex, salt, sugar
examples of steriods
aldosterone, cortisol, estrogen
amino acid derived hormones
small peptide hormones from 1 amino acid
ex: T3 and T4 are tyrosine deriviatives and are lipid soluble
catecholamines
hormone derived from tyrosine and are hydrophilic
- norepinephrine and epinephrine
what hormone is derived from tryptophan and is both lipid and water soluble
melatonin
tropic hormones
cause the release of downstream hormones
hypothalamus anterior pituitary adrenal axis
Crh –> acth –> cortisol
- cortisol inhibits CRH and ACTH
which hormone exhibits positive feedback
oxytocin during labor contractions
insulin
peptide hormone released by beta cells of pancreas that cause cell uptake of glucose and decrease BGL
- activate glucose transporters
what processes does insulin upregulate
glycolysis, glycogen synthesis, fatty acid synthesis
what processes does insulin inhibit
glycogenolysis, fatty acid degredation (lipolysis), fatty acid oxidation
glucagon
peptide hormone released by alpha cells of pancreas and is opposite of insulin
- released in response to low BGL and encourages release of glucose from cells into the blood